Control system



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3g a fig Li 5 & -3 2 $5 2 2 Q Q: Q MM 1 N R! N E 1A INEENTOR R. K. CROOKS CONTROL SYSTEM Filed June 22. 1951 2 Sheets-Sheet 1 Oct. 29, 1935. R. K. CROOKS CONTROL SYSTEM Filed June 22, 1931 Q 2 Sheets-Sheet 2 INVENTOR BY H/S ATTORNEY Patented Oct. 29, 1935 UNITED STATES PATENT OFFICE CONTROL SYSTEM Application June 22, 1931, Serial No. 545,917

8 Claims. This invention relates to control systems, and,

although it has been primarily designed for employment in connection with brake-control means on trains, its utility is by no means to be limited v.to such function asit is susceptible of use in ing the integrity of one or more circuits that :control normally deenergized translating means without, however, energizing said translating means when testing the circuit or circuits.

In the accompanying drawings the invention is disclosed in several concrete and preferred forms,

in which Fig. 1 is a diagrammatic view of the circuits constituting one form of the invention; and

Fig. 2 is a view similar to Fig. 1 but showing a more elaborate form of the invention.

In the exemplification shown in the drawings, there are two circuits which here have one path in common, said path being conveniently indicated by conductor C, reference characters A and B indicating line wires which in conjunction :with common path C and other devices to be presently described constitute two line circuits. These line circuits may be conceived as extending from a control station D to a remote station E, and in the present instance said control station is one of a plurality of cars, such as the cab of the engine, and said remote station is another one of a plurality of cars, such as the caboose of a train. Any number of intervening cars may, of course, be present, and it will be seen that the line circuits extend from car to car. M

indicates a translating device, here a trafiic-controlling device such as a brake-control magnet, connected across conductors A and C. M indicates a similar translating device connected '-'across conductors B and C. M and M are of the type of brake-control means that are normally deenergized, and which when energized apply the brakes. Any suitable means may be provided to energize M and M. In the present instance is shown a source of direct current having one lead 0 connected to path C and the other lead 0 connected through wires 0 and M V to either one or both of line conductors B and A. The arrangement is here such that when the engineers brake valve V is in the position shown in the drawings, that is in release, running or holding position, the contacts are 'open and no current is supplied to the line wires, but that when valve V is moved to bring contacts v v and v into engagement with contacts 0 v and v current is supplied to both M and M to thereby energize them and give a service appli-' cation of the brakes. When valve V is moved into an intermediate or lap position in which contacts 12 and v are in engagement with con- 5 tacts v and 0 but in which contacts 0 and v are out of engagement, M only is energized whereby the brake application already made is maintained.

It will be understood that with such con- 10 struction it is desirable to provide means for testing the integrity of the line conductors so that the engineer may be assured at all times that the brakes will function if operated. Also, on long freight trains, it is desirable that the crew in the caboose be kept informed as to the dependability of the brakes.

Accordingly, the following means, or their equivalent, are provided to test the integrity of the line circuit:

Referring first to Fig. 1, the three line conductors (A, B and C) are connected in multiple by a cross conductor l-8 at the control station and by a similar cross conductor l2l3 at the remote station, and provision is made whereby these elements constitute an unbalanced Wheatstone bridge. This provision here consists in locating two relays G and H in the cross conductors aforesaid, each of said relays having two windings of unequal impedance, said windings being denoted respectively by MM, NN, PP and RR. These windings are reversely arranged, when considering the direction of the flow of current, with respect to each other, so thatif current flows in a given and the same direction, at the same time, through both 1-8 and l2l3, said current will encounter high impedance MM first in one cross conductor and low impedance PP first in the other cross conductor, and conversely, when flowing in the other direction it will encounter low impedance NN first in one cross conductor and high impedance RR first in the other conductor. In either event, the result is that points 00 and QQ in the two cross conductors will be at different potential and consequently current my G it will also flow in the same direction through relay H via line wires A and B, and that current will likewise flow over line wire C to equalize the potential at points and QQ. The

primary of transformer T is included in a supply circuit'consi'sting here of generator AC, wire I, primary of transformer T; wire 2, switch S and Wire .5 back to AC, and it will be understood that, when S is closed, current will flow from AC to energize primary of transformer T. Any suitable indication means may be employed to denote the integrity or lack of integrity of the line said circuit closer or armature 32. Circuit-closer or armature 3,4 is controlled by slow acting D. C.

relay D interposed" in conductor Candsupplied with current by rectifier J.

however, that saidshunt around S is by no means essential when other indication means are provided. Such other indication means here take the form of lamps I? and I which are interposed in conductor C, the continuity of said conductor being controlled by an armature or circuit closer I9 controlled by relay H, which latter is of the type thatrequires both of its windings to be effectively energized to enable .it to pick up its armature. It will likewise be understood that signals 1 and I are not essential if the shunt around switch S is provided, but it will likewise beunderstood that, both the shunt and the signals may be used to advantage.

Suitable blocking or filtering means, such as are well known in theart, may be inserted in the various leads to separate the current of source 0 from that of transformer T. In the present instance condensers C C C and C are inserted in the'cross conductors, and are of such capacity as to cause series resonance in the circuit means atthe particular frequency of alternating current used. Condenser C inserted in wire is also a blocking means for the direct current, but

in addition has the function of preventing current from reaching a high value if conductors A and B become short-circuited. i 6 choke coils interposed in the leads from source 0,

indicates and magnets M and M have a very high im-' pedance'to prevent flow of alternating current V therethrough.

v To start the system in operation, switch s is closed thereby energizing transformer current from the secondary of the latter will now flow'over wire 6, through cross conductors 1-8, and relay G, over wires 9 and i0 back to secondary; Current will also flow from secondary or T, over wire 6, conductor A, cross conductors l2--l3 and relay H, conductor B and wires 9' and I0 back to secondary of T. Energization of relays G and .Hwill lift armatures 32 andldarmature 32 closing the shunt over switch S at one point, and armature I9 closing-the connection through 70,

conductor-C. Current-"will; now flow over conductor C and will light signals I and I and will, 1 fby means ofjreetifier J, energize slow-acting relay D thereby raising armature 34 and closing the shunt around switch S,*'which switch may nowbe opened manually:

It will be understood,

relays G and'H will at U and U flow over wire 6, conductor A, short circuit U and The effect of various failures in the integrity of the system will now be considered. 7

If conductor A is open, say at U, current from secondary of transformer T will continue to flow through relay G but will cease to flow through 5 winding PP of relay H. Relay H therefore becomes deenergized and armature 19 will drop thereby rupturing the circuit through C, which, in turn, extinguishes lights I and I andafter a predetermined period deenergizes relay D thereby dropping armature 34. The dropping of armature 34 ruptures the shunt around switch S and cuts off. supply of current from AC to T, thereby deenergizingrelay G and causing its armature 32 to drop. The system is now out of operation, but has given indication both on the engine and in the caboose of its inoperativeness.

If conductor B is open, say at U winding RR will receive no current, relay H'will become deen-' ergized sufficiently to drop armature=l9 and the same results as those previously described will take place r If conductor C is open, say at U, current will cease to flowvtherein, lights I and I will become extinguished andafter apredetermined period re- 25, lay D will become deenergized, thereby dropping armature 34 and opening the shunt around S. This, in turn, will cut off current from AC to '1, become deenergized, and armatures 32 and I9 will drop. I

If conductors A and C are shortecircuited, say current from secondary or T will U conductor C, winding NN of relayG, conductor 8, and wires 9 and former T. As both windings of G are not :energized, armature 32 will drop thereby cutting of! supply of current from AC to T and so rendering the system inoperative, lights I and I being extinguished and armature 34 droppingafter .a. pre- 40 determined period. 7 a

' If conductors B and C are short-.circuited, say at the points U and '0, current will flow from secondary of transformer T through winding MM of relay G, along conductor C, short circuit U and: U conductor B and wires 9 and I0 backto secondary of transformer T. Therefore, annature' 32 will drop with the results previously described.

If conductors A and B are short-circuited, say

at U and U a very low impedancepath is .cre- .50 ated in consequence of which relay G- willnot re,-

ceive suflicient current to hold up armature 32,

which latter therefore drops with the resultant eflfefct previously set forth.

' If either condenser C or C becomes shorted relay G is detuned from resonance to such anex tent that itdrops its armature 32. The result of this has already been. explained. If either condenser .C orC is fshorted, relay H is detunedfrom resonance and drops armature l8. Lights I and I are therefore extinguished and, after. an

interval of time, relay D becomes deenergized and dropslits armature 34 thereby opening'the :cir-

cuit betweenAC and T. The remaining stepsjneed i not be repeated here. A 7 -X and Y indicate keys in conductor .C,.o f which keys there may be anynumber; It will be under stood that. by opening and, closing any once! said keys accordinglto aprearranged code, signaling- J may be effected between the stationsor between V an intermediategpoint and bothstationss Mo mentary'opening of a' key such as IX or'Y will extinguish indication lamps I andl 'because current will no long er fiow in conductor C, but, up;

IE) back to secondary'of tran'sowing to the fact that D is a slow-release relay,

' it will not drop its armature 34 (unless the key is kept open long enough to consume the retardation period of D and the remainder of the circuits therefore is unaffected.

It will be seen from the foregoing that the system described is relatively simple and constitutes a safeguard whereby failure in integrity of the line conductors will be revealed at one or both ends of the line and at any intermediate point if so desired. The use of a rectifier in the system to supply relay D with current needs perhaps some additional consideration. It will be remembered that, when a short-circuit occurs beween line conductors A and. C or B and C, a low impedance shunt is established around one or the other of the windings of relay G, and attention is called to the fact that this low impedance shunt passes through rectifier J. Thus, if the short circuit is between A and C, current from T instead 01 passing through winding MM of G will pass from A to C (say at U and U and will then fiow along conductor C through lamp I rectifier J and relay D to point 00, Winding NN, and thence by wires 8, 9 and 10 back to secondary of T. If the short-circuit is between B and C, current from T will pass through winding MM to point 00, thence through relay D rectifier J and lamp I by way of conductor C, from C to B (say at U and U and thence by wires 9 and I back to secondary of T. If the rectifier be of the copper'oxide type, its ohmic resistance may increase with age, and, should this happen, the impedance intended to shunt one of the windings of relay G may be .too high to cause said relay G to drop its armature. Consequently the short-circuit of the line conductors would not be detected. This condition can easily be cured by arranging light I and rectifier J in multiple instead of in series and by making light I of low resistance as will be apiparent, because in that case the low impedance shunt would be through the light and not through the rectifier and an increase in the ohmic resistance' of rectifier J would therefore'be immaterial. Such an arrangement would, however, have a disadvantage in that if indicator light I becomes open under normal conditions) the system would still remain operative but the engineman would receive what might be called a false danger indication by the extinguishing of the light.

In order to avoid all of these disadvantages, the arrangement disclosed in Fig. 2 is proposed. Fig. 2 shows basically an arrangement exactly like the disclosure in Fig. 1 but with certain additions. arrangement shown in Figs. 1 and 2 it is unnecessary to repeat the description of the system as a whole, and only the additional elements employed in Fig. 2 and their effect upon the system will be pointed out. Briefly, the additional elements consist of two low impedance paths, from conductor C, that shunt the windings of relay H, said paths being controlled by armatures of relay H and by armatures of an additional relay inserted in conductor C. To be specific: K indicates a rectifier and E a D. C. slow-release relay connected in series with light I between key Y and armature I9. 24 is an armature of relay E which when in its up-position closes the break between wires 25 and 23. 21 is a similar armature which in its up-position closes a break between wires 25 and. 28. 22 is an armature, controlled by relay H, that in its downposition engages a back contact to close the break between wires 23 and 2|, the latter of which is In view of the close similiarity of the connected to wire I 2. So likewise 29 is a second armature, under the control of relay H, that in its down position engages a back contact to close the break between wires 28 and 30, the latter of which is connected to wire l3. be seen that, when the system is operating normally, relay H is energized and armatures 22 and 29 are up and the two low impedance paths from-C are therefore open. Relay E being also energized, armatures 24 and 21 are in the up or closed position. Under normal conditions the system of Fig. 2 will operate exactly as described in connection with the system of Fig. 1, except that an additional rectifier (K) and an additional relay (E are energized. However, when the integrity of the circuits fails, a somewhat different current flow from that described in connection with Fig. 1 takes place in the arrangement of Fig. 2.

Taking up first the condition of a break in conductor A, say at point U, it will be evident that winding PP of relay H will not be energized. As a result of this, armature l9 drops opening the normal path to C, and armatures 22 and 29 likewise drop thereby closing the low impedance paths to C. Current. from the secondary of transformerT will, however, flow through the windings of relay G, and in addition current will flow from point 00 over conductor C, and the various instrumentalities associated therewith, to 30 wire 25, armature 2?, wire 28, armature 29,- wires 30 and I3, conductor 13, and wires 9 and I0 back to secondary of T. It will be noted that relay E no longer receives current because armature I9 is down, and hence, after a certain lapse of time, 85 relay E becomes deenergized and drops armatures 24 and 21 thus opening the low impedance paths from C. Likewise relay D will after a given period drop its armature 34, thereby rupturing the supply circuit to transformer T and so rendering the system inoperative. Lights I and I will, of course, also have become extinguished.

If conductor B is open, say at U current will flow through both windings of relay G as before, but not through winding RR of relay H. The armatures of relay H therefore drop and current will flow over conductor C from point 00, to wire 25, armature 24, Wire 23, armature 22, wires 2| and I2 to A and thence back to secondary of transformer T. Upon the expiration of the release period of relay E armatures 24 and 27 will drop thereby extinguishing lights I and P and causing deenergization of relay D so that the latter drops its armature 34 and renders the system inoperative.

If conductor C is ruptured, say at U current at once ceases to flow therein, lights I and I are extinguished and relay D drops armature 34, after a lapse of time, thereby opening the circuit that supplies current to transformer T and so rendering the system inoperative.

If conductors A and C are short-circuited, say at U and U the current from secondary of transformer T will not flow through winding PP of relay H but will cross over from A to C. Consequently armatures I9, 22 and 29 drop and, relay E being slow in its release, the following circuit is established: From secondary oftransformer T, by way of conductor A, short-circuit U-U, conductor 0, wire 25, armature 21, wire 28, armature 29, wires 39 and I3, conductor B, and wires 9 and 16 back to secondary of transformer T. Thus relay G is bridged by a very g It will now 5 7 low impedance path that does not include any rectifier, and consequently armature 32 drops thereby opening the supply circuit to transformer T, all relays drop and lights I and I? are extinguished;

If a short-circuit occurs between conductors B remains energized and holds up its armatures, [the following circuit will be established: from secondary of transformer 1, "over wire A, wires I2 and. 2|, armature 22, wire 23, armature 24, wire 25, conductorC, short-circuit U -U .,-conductor B, and wires 9 and I0 back to secondary of transformer T. Hereagain, a low' impedance path devoid of rectifiers bridges relay G and con- 7 sequently armature 32 I rendered inoperative in the manner previously.

drops and the system is described.

If conductors A and B are I at U andU relay G at once drops :its armature 32 because said relay will be bridged bytheshort circuit which would constitute a low impedance path, and the system is rendered inoperative.

If condensers C or C associated with relay G become short fcircuited, the relay winding which the particular condenser tunes to resonance will become detuned, and the current flowing in the winding is diminished to such an extent that armature 32 drops and the system is rendered If condensers C or C H is short circuit'ed then inoperative as before. associated with relay armatures I9, 22 and 29 drop and the following circuit is established: From secondary of transformer T over conductor A, wires l2 and 2 l armature 22, wire 23, armature 24, wire 25, armature Z'Lwire 28, armature 29, wires 30 and I3, conductor B and wires 9 and I0 back to secondary of T. Armature 32 therefore drops with the result previously described.

If there be an open circuit on any of the coni densers C C C and 0*, then the relay winding 7 with which the particular condenser is associated becomes deenergized and the armature con,- trolled by such relay drops thereby rendering the system inoperative'inthe manner previously set forth. V 7 It will be apparent that; in the case oithe arrangement of Fig. 2, signaling can likewise be carried on by means of keys X, Y because both relays D and E are of the slow-release type. 'I claim: 7 1. A control system including: two line conductors extending from one station to-another, a cross conductor at each station connecting the two line conductors, a third line conductor extend ing from a point having a one cross conductor to a point having a difierent potential on theother cross conductorto thereby in effect constitute the bridge element of an un' balanced Wheatstone bridge, a circuit including a current source to supply current to said line con ductors, two relays the winding of one of which is 'inclu'deii-in 'one of the cross conductors and the winding of the other of which is included in the third'line conductor, and armatures operated 'by said relays for disconnectingsaid circuitfromsaid line'conductors when either one or both of T said relays are deenergized. r v r, '2. A'control system including: "two line'conductors'ext'ending from one station to another,

, means for creating a difference of potential'across said conductors," two relays, eachhaving two windings of unequal impedance, the two windings short-circuited, say 7 certain potential on of one relay being connected in series in one relative arrangement across the two line conductors at the other station, to thereby create points of unequal potential in the two relays intermediate the two windings, a third line conductor extending from a point intermediate the two windings 01 one relay to apoint intermediate the two windings of the other relay, indication means interposed in the :third line conductor controlled by the flow-of' current in said third line conductor to denote the integrity or lack of integrity of said line conductors, and armatures controlled by said relaysoperative to disconnect said potentialcreating meansfrom said line conductors when eitherone or both of said relays are deenergized.

3. A control system including: two line conductors extending from one station toanother,- means forcreating a difference of potential across said conductors, two relays, each having two windings of unequal impedance, thetwowindings oflone relay being connected in series-in one relative arrangement across the two linexconductors at one station and the two windings of the other relay beingconnected in series in the other relative arrangement across the two line v conductors at the other station, to thereby create points of unequal potential'in the two relays in termediate' the'two windings, a third line conducitorextending from a point intermediate the two windings of one relay to a point intermediate the two windings of the other relay, a relay in the third line conductor, and indicationmeans controlled by' saidrelays and effective for'indicating integrity of said line conductors when and only when all threecrelays are energized.

4. A control systemincluding: twoline conductors extending from one station to another, means for creating a difference of potential across said conductors, two relays, each having two windings of unequal impedance, the two windotherrelay being connected in series in the other relative arrangement across the two line condllCtOrS1atllh,OthB1' station, to thereby create points of unequal potential in the two relays intermediate the two windings, a third line conductors extending from a point intermediate the ,ingsof one relay being connected in series in one.

two windings of one relay to a point intermediate Y the two windings'of the other relay, an armature controlled by one ofthe relays for disconnecting saidthird lineconductor when said one relay is deenergized, and an armature controlled by the other of said relays for disconnecting said potential creating means when said other relay is deenergized, g v :5. 'A control system including: twoline conductors extending from one station to another, means for creating a difference of potential across said ;.conductors, two relays, each having twowindi'ngs 'of unequal impedance, the two windings of ,onerelay being connected in-r series in one relative arrangement across the-two line "conductors at one station and the two windings j of the other relay being connected in serie'sin,

the other relative arrangement across the two linesconductors at the other station, to thereby fer-sate points of unequal potential in the two relays intermediate the two windings, a third lineconductor extending from a point interme-t diate the two windings of one relay'toa point in 75 termediate the two windings or the other relay, indication means interposed in the third line conductor controlled by the flow of current in the third line conductor to denote the integrity or lack of integrity of the line conductors, an armature controlled by one of the relays for disconnecting said third line conductor when said one relay is deenergized, and an armature controlled by the other of said relays for disconnecting said potential creating means when said other relay is deenergized.

6. A control system including: two line conductors extending from one station to another, means for creating a difference 01 across said conductors, two relays, each having two windings of unequal impedance, the two windings of one relay, being connected in series in one relative arrangement across the two line conductors at one station and the two windings of the other relay being connected in series in the other relative arrangement across the two line conductors at the other station, to thereby create points of unequal potential in the two relays intermediate the two windings, a third line conductor extending from a point intermediate the two windings of one relay to a point intermediate the two windings of the other relay, a circuit closing armature interposed in the third line conductor, controlled by one of the relays and held closed only so long as both of the windings of said relay are efiectively energized, and a circuit closing armature controlled by the other of said relays for connecting said potential creating means to said two line conductors and held closed only so long as both of the windings of said other relay are efiectively energized.

7. A control system including: two line conductors extending from one station to another, means for creating a diflerence of potential across said conductors, two relays, each having two windings of unequal impedance, the two windings of one relay being connected in series in one relative arrangement across the two line conductors at one station and the two windings of the other relay being connected in series in the other relative arrangement across the two line conductors at the other station, to thereby potential I create points of unequal potential in the two relays intermediate the two windings, a third line conductor extending from a point intermediate the two windings of one relay to a point intermediate the two windings of the other relay, 5

two windings of unequal impedance, the two 15.

windings 01' one relay being connected in series in one relative arrangement across the two line conductors at one station and the two windings of the other relay being connected in series in the other relative arrangement across the two 20 line conductors at the other station, to thereby create points of unequal potential in the two relays intermediate the two windings, a third line conductor extending from a point intermediate the two windings of one relay to a point intermediate the two windings of the other relay,

a low impedance path connected to the third line conductor and bridging the windings of one of the relays, circuit closing means in said path held in open position as long as the windings 01 the relay so bridged are energized, a relay in the third line conductor, circuit closing means in said path held in closed position as long as the relay in the third line conductor remains energized, a, circuit closing armature in the third line conductor held in closed position as long as the windings 01' the relay that is bridged by the low impedance path remains energized, indicating means interposed in the third line conductor responsive to the current flow therein to denote the integrity or lack or integrity of said line conductors, and a circuit closing armature held in a closed position as long as the winding of the other of the first two mentioned relays remains energized to connect the potential creating means to said two line conductors.

RALPH KENT CROOKS. 

